Keitaro Watanabe

Improving salt tolerance of cotton seedlings with 5-aminolevulinic acid

Of 12 different plant growth regulators (PGRs) tested,5-aminolevulinic acid (ALA) was found to improve the salttolerance of cotton seedlings. Cotton seedlings treated with ALAcould grow in soil containing levels as high as 1.5% (wt/wt)NaCl. The analyses of mineral compositions of plant parts revealed that the Naplus concentrations in the roots of the plantstreated with ALA were suppressed to low concentrations. Fromthese results, it can be presumed that the presence of ALA maycause a reduction of Naplus uptake.

Formation of 5-aminolevulinic acid under aerobic/dark condition by a mutant ofRhodobacter sphaeroides

SummaryA mutant strain CR-17 ofRhodobacter sphaeroides was characterized by the low activity of 5-aminolevulinic acid dehydratase (ALAD) compared to the wild-type strain. Without addition of levulinic acid (inhibitor of ALAD), the mutant secreted 5-aminolevulinic acid under anaerobic/light (64.5 μM) or under microaerobic/dark (32 μM) conditions; 82.5 μM of ALA was secreted under aerobic/dark condition with addition of 15 mM levulinic acid.